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   &#160;<span id="projectnumber">Version 1.03</span>
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<div class="header">
  <div class="summary">
<a href="#define-members">Macros</a> &#124;
<a href="#func-members">Functions</a>  </div>
  <div class="headertitle">
<div class="title">Signal Events<div class="ingroups"><a class="el" href="group__CMSIS__RTOS__InterThread.html">Inter-Thread Communication and Resource Sharing</a></div></div>  </div>
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<p>Synchronize threads using signals.  
<a href="#details">More...</a></p>
<table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="define-members"></a>
Macros</h2></td></tr>
<tr class="memitem:ga01edde265710d883b6e237d34a6ef4a6"><td class="memItemLeft" align="right" valign="top">#define&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__SignalMgmt.html#ga01edde265710d883b6e237d34a6ef4a6">osFeature_Signals</a>&#160;&#160;&#160;8</td></tr>
<tr class="memdesc:ga01edde265710d883b6e237d34a6ef4a6"><td class="mdescLeft">&#160;</td><td class="mdescRight">maximum number of Signal Flags available per thread  <a href="#ga01edde265710d883b6e237d34a6ef4a6">More...</a><br/></td></tr>
<tr class="separator:ga01edde265710d883b6e237d34a6ef4a6"><td class="memSeparator" colspan="2">&#160;</td></tr>
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<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a>
Functions</h2></td></tr>
<tr class="memitem:ga3de2730654589d6c3559c4b9e2825553"><td class="memItemLeft" align="right" valign="top">int32_t&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__SignalMgmt.html#ga3de2730654589d6c3559c4b9e2825553">osSignalSet</a> (<a class="el" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a> thread_id, int32_t signals)</td></tr>
<tr class="memdesc:ga3de2730654589d6c3559c4b9e2825553"><td class="mdescLeft">&#160;</td><td class="mdescRight">Set the specified Signal Flags of an active thread.  <a href="#ga3de2730654589d6c3559c4b9e2825553">More...</a><br/></td></tr>
<tr class="separator:ga3de2730654589d6c3559c4b9e2825553"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:ga87283a6ebc31ce9ed42baf3ea7e4eab6"><td class="memItemLeft" align="right" valign="top">int32_t&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__SignalMgmt.html#ga87283a6ebc31ce9ed42baf3ea7e4eab6">osSignalClear</a> (<a class="el" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a> thread_id, int32_t signals)</td></tr>
<tr class="memdesc:ga87283a6ebc31ce9ed42baf3ea7e4eab6"><td class="mdescLeft">&#160;</td><td class="mdescRight">Clear the specified Signal Flags of an active thread.  <a href="#ga87283a6ebc31ce9ed42baf3ea7e4eab6">More...</a><br/></td></tr>
<tr class="separator:ga87283a6ebc31ce9ed42baf3ea7e4eab6"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:ga38860acda96df47da6923348d96fc4c9"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__CMSIS__RTOS__Definitions.html#structosEvent">osEvent</a>&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__SignalMgmt.html#ga38860acda96df47da6923348d96fc4c9">osSignalWait</a> (int32_t signals, uint32_t millisec)</td></tr>
<tr class="memdesc:ga38860acda96df47da6923348d96fc4c9"><td class="mdescLeft">&#160;</td><td class="mdescRight">Wait for one or more Signal Flags to become signaled for the current <b>RUNNING</b> thread.  <a href="#ga38860acda96df47da6923348d96fc4c9">More...</a><br/></td></tr>
<tr class="separator:ga38860acda96df47da6923348d96fc4c9"><td class="memSeparator" colspan="2">&#160;</td></tr>
</table>
<a name="details" id="details"></a><h2 class="groupheader">Description</h2>
<p>Signals are used to trigger execution states between threads. The signal management functions in CMSIS-RTOS allow you to control or wait for signal flags. Each thread has up to 31 assigned signal flags. The maximum number of signal flags is defined in the <a class="el" href="cmsis__os_8h.html">cmsis_os.h</a> file (<b>#define osFeature_Signals</b>).</p>
<p>A thread</p>
<ul>
<li>can wait for signals to be set (using <a class="el" href="group__CMSIS__RTOS__SignalMgmt.html#ga38860acda96df47da6923348d96fc4c9">osSignalWait</a>). Using this function, it enters the <a class="el" href="group__CMSIS__RTOS__ThreadMgmt.html#ThreadStates">WAITING</a> state. The <a class="el" href="group__CMSIS__RTOS__SignalMgmt.html#ga38860acda96df47da6923348d96fc4c9">osSignalWait</a> parameter <em>signals</em> defines the signals that are required to put the thread back into <b>READY</b> state.</li>
<li>may set one or more flags in any other given thread (using <a class="el" href="group__CMSIS__RTOS__SignalMgmt.html#ga3de2730654589d6c3559c4b9e2825553">osSignalSet</a>).</li>
<li>may clear its own signals or the signals of other threads (using <a class="el" href="group__CMSIS__RTOS__SignalMgmt.html#ga87283a6ebc31ce9ed42baf3ea7e4eab6">osSignalClear</a>).</li>
</ul>
<p>When a thread wakes up and resumes execution, its signal flags are automatically cleared.</p>
<h2>Working with Signals </h2>
<p>Here is a simple example that shows how two thread can communicate with each others using signals:</p>
<div class="image">
<img src="simple_signal.png" alt="simple_signal.png"/>
<div class="caption">
Simple signal event communication</div></div>
<p> The following steps are required to use signals:</p>
<ol type="1">
<li>In the thread (for example thread ID <code>tid_thread1</code>) that is supposed to wait for a signal, call the wait function: <div class="fragment"><div class="line"><a class="code" href="group__CMSIS__RTOS__SignalMgmt.html#ga38860acda96df47da6923348d96fc4c9">osSignalWait</a> (0x0001, <a class="code" href="cmsis__os_8h.html#a9eb9a7a797a42e4b55eb171ecc609ddb">osWaitForever</a>); <span class="comment">// wait forever for the signal 0x0001</span></div>
</div><!-- fragment --></li>
<li>In another thread (or threads) that are supposed to wake the waiting thread up call: <div class="fragment"><div class="line"><a class="code" href="group__CMSIS__RTOS__SignalMgmt.html#ga3de2730654589d6c3559c4b9e2825553">osSignalSet</a> (tid_thread1, 0x0001);    <span class="comment">// set the signal 0x0001 for thread tid_thread1</span></div>
<div class="line"><a class="code" href="group__CMSIS__RTOS__Wait.html#ga02e19d5e723bfb06ba9324d625162255">osDelay</a> (1000);                       <span class="comment">// wait for 1 second</span></div>
</div><!-- fragment --> </li>
</ol>
<h2 class="groupheader">Macro Definition Documentation</h2>
<a class="anchor" id="ga01edde265710d883b6e237d34a6ef4a6"></a>
<div class="memitem">
<div class="memproto">
      <table class="memname">
        <tr>
          <td class="memname">#define osFeature_Signals&#160;&#160;&#160;8</td>
        </tr>
      </table>
</div><div class="memdoc">
<p>The CMSIS-RTOS API may support a variable number of signal flags. This define specifies the number of signal flags available per thread. The maximum value is 32 signal flags per thread.</p>
<p><a class="el" href="rtxImplementation.html">CMSIS-RTOS RTX</a> Setting: <b>osFeature_Signals</b> is 16 </p>

</div>
</div>
<h2 class="groupheader">Function Documentation</h2>
<a class="anchor" id="ga87283a6ebc31ce9ed42baf3ea7e4eab6"></a>
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          <td class="memname">int32_t osSignalClear </td>
          <td>(</td>
          <td class="paramtype"><a class="el" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a>&#160;</td>
          <td class="paramname"><em>thread_id</em>, </td>
        </tr>
        <tr>
          <td class="paramkey"></td>
          <td></td>
          <td class="paramtype">int32_t&#160;</td>
          <td class="paramname"><em>signals</em>&#160;</td>
        </tr>
        <tr>
          <td></td>
          <td>)</td>
          <td></td><td></td>
        </tr>
      </table>
</div><div class="memdoc">
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramdir">[in]</td><td class="paramname">thread_id</td><td>thread ID obtained by <a class="el" href="group__CMSIS__RTOS__ThreadMgmt.html#gac59b5713cb083702dce759c73fd90dff">osThreadCreate</a> or <a class="el" href="group__CMSIS__RTOS__ThreadMgmt.html#gab1df2a28925862ef8f9cf4e1c995c5a7">osThreadGetId</a>. </td></tr>
    <tr><td class="paramdir">[in]</td><td class="paramname">signals</td><td>specifies the signal flags of the thread that shall be cleared. </td></tr>
  </table>
  </dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>previous signal flags of the specified thread or 0x80000000 in case of incorrect parameters or call from ISR. </dd></dl>
<dl class="section note"><dt>Note</dt><dd>MUST REMAIN UNCHANGED: <b>osSignalClear</b> shall be consistent in every CMSIS-RTOS.</dd></dl>
<p>Clear the signal flags of an active thread.</p>
<dl class="section note"><dt>Note</dt><dd>Cannot be called from <a class="el" href="functionOverview.html#CMSIS_RTOS_ISR_Calls">Interrupt Service Routines</a>.</dd></dl>
<p><b>Code Example</b> </p>
<div class="fragment"><div class="line"><span class="keywordtype">void</span> Thread_2 (<span class="keywordtype">void</span> <span class="keyword">const</span> *arg);</div>
<div class="line"></div>
<div class="line"><a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaee93d929beb350f16e5cc7fa602e229f">osThreadDef</a> (Thread_2, <a class="code" href="cmsis__os_8h.html#ga7f2b42f1983b9107775ec2a1c69a849aa914433934143a9ba767e59577c56e6c2">osPriorityHigh</a>, 1, 0);</div>
<div class="line"> </div>
<div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span> EX_Signal_1 (<span class="keywordtype">void</span>)  {</div>
<div class="line">  int32_t  signals;</div>
<div class="line">  <a class="code" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a> thread_id;</div>
<div class="line">  </div>
<div class="line">  thread_id = <a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gac59b5713cb083702dce759c73fd90dff">osThreadCreate</a> (<a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaf0c7c6b5e09f8be198312144b5c9e453">osThread</a>(Thread_2), NULL);</div>
<div class="line">  <span class="keywordflow">if</span> (thread_id == NULL)  {</div>
<div class="line">    <span class="comment">// Failed to create a thread.</span></div>
<div class="line">  }</div>
<div class="line">  <span class="keywordflow">else</span>  {</div>
<div class="line">f    :</div>
<div class="line">    signals = <a class="code" href="group__CMSIS__RTOS__SignalMgmt.html#ga87283a6ebc31ce9ed42baf3ea7e4eab6">osSignalClear</a> (thread_id, 0x01);</div>
<div class="line">  }</div>
<div class="line">}</div>
</div><!-- fragment --> 
</div>
</div>
<a class="anchor" id="ga3de2730654589d6c3559c4b9e2825553"></a>
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          <td class="memname">int32_t osSignalSet </td>
          <td>(</td>
          <td class="paramtype"><a class="el" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a>&#160;</td>
          <td class="paramname"><em>thread_id</em>, </td>
        </tr>
        <tr>
          <td class="paramkey"></td>
          <td></td>
          <td class="paramtype">int32_t&#160;</td>
          <td class="paramname"><em>signals</em>&#160;</td>
        </tr>
        <tr>
          <td></td>
          <td>)</td>
          <td></td><td></td>
        </tr>
      </table>
</div><div class="memdoc">
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramdir">[in]</td><td class="paramname">thread_id</td><td>thread ID obtained by <a class="el" href="group__CMSIS__RTOS__ThreadMgmt.html#gac59b5713cb083702dce759c73fd90dff">osThreadCreate</a> or <a class="el" href="group__CMSIS__RTOS__ThreadMgmt.html#gab1df2a28925862ef8f9cf4e1c995c5a7">osThreadGetId</a>. </td></tr>
    <tr><td class="paramdir">[in]</td><td class="paramname">signals</td><td>specifies the signal flags of the thread that should be set. </td></tr>
  </table>
  </dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>previous signal flags of the specified thread or 0x80000000 in case of incorrect parameters. </dd></dl>
<dl class="section note"><dt>Note</dt><dd>MUST REMAIN UNCHANGED: <b>osSignalSet</b> shall be consistent in every CMSIS-RTOS.</dd></dl>
<p>Set the signal flags of an active thread. This function may be used also within interrupt service routines.</p>
<dl class="section note"><dt>Note</dt><dd><a class="el" href="functionOverview.html#CMSIS_RTOS_ISR_Calls">Interrupt Service Routines</a> can call this function.</dd></dl>
<p><b>Code Example</b> </p>
<div class="fragment"><div class="line"><span class="keywordtype">void</span> Thread_2 (<span class="keywordtype">void</span> <span class="keyword">const</span> *arg);</div>
<div class="line"> </div>
<div class="line"><a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaee93d929beb350f16e5cc7fa602e229f">osThreadDef</a> (Thread_2, <a class="code" href="cmsis__os_8h.html#ga7f2b42f1983b9107775ec2a1c69a849aa914433934143a9ba767e59577c56e6c2">osPriorityHigh</a>, 1, 0);</div>
<div class="line"> </div>
<div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span> EX_Signal_1 (<span class="keywordtype">void</span>)  {</div>
<div class="line">  int32_t signals;</div>
<div class="line">  uint32_t exec;</div>
<div class="line">  <a class="code" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a> thread_id;</div>
<div class="line">  </div>
<div class="line">  thread_id = <a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gac59b5713cb083702dce759c73fd90dff">osThreadCreate</a> (<a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaf0c7c6b5e09f8be198312144b5c9e453">osThread</a>(Thread_2), NULL);</div>
<div class="line">  <span class="keywordflow">if</span> (thread_id == NULL)  {</div>
<div class="line">    <span class="comment">// Failed to create a thread.</span></div>
<div class="line">  }</div>
<div class="line">  <span class="keywordflow">else</span>  {</div>
<div class="line">    signals = <a class="code" href="group__CMSIS__RTOS__SignalMgmt.html#ga3de2730654589d6c3559c4b9e2825553">osSignalSet</a> (thread_id, 0x00000005);         <span class="comment">// Send signals to the created thread</span></div>
<div class="line">  }</div>
<div class="line">}</div>
</div><!-- fragment --> 
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          <td class="memname"><a class="el" href="group__CMSIS__RTOS__Definitions.html#structosEvent">osEvent</a> osSignalWait </td>
          <td>(</td>
          <td class="paramtype">int32_t&#160;</td>
          <td class="paramname"><em>signals</em>, </td>
        </tr>
        <tr>
          <td class="paramkey"></td>
          <td></td>
          <td class="paramtype">uint32_t&#160;</td>
          <td class="paramname"><em>millisec</em>&#160;</td>
        </tr>
        <tr>
          <td></td>
          <td>)</td>
          <td></td><td></td>
        </tr>
      </table>
</div><div class="memdoc">
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramdir">[in]</td><td class="paramname">signals</td><td>wait until all specified signal flags set or 0 for any single signal flag. </td></tr>
    <tr><td class="paramdir">[in]</td><td class="paramname">millisec</td><td><a class="el" href="functionOverview.html#CMSIS_RTOS_TimeOutValue">Timout Value</a> or 0 in case of no time-out. </td></tr>
  </table>
  </dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>event flag information or error code. </dd></dl>
<dl class="section note"><dt>Note</dt><dd>MUST REMAIN UNCHANGED: <b>osSignalWait</b> shall be consistent in every CMSIS-RTOS.</dd></dl>
<p>Suspend the execution of the current <b>RUNNING</b> thread until all specified signal flags with the parameter <em>signals</em> are set. When the parameter <em>signals</em> is 0 the current <b>RUNNING</b> thread is suspended until any signal is set. When these signal flags are already set, the function returns instantly. Otherwise the thread is put into the state <b>WAITING</b>. Signal flags that are reported as event are automatically cleared.</p>
<p>The argument <em>millisec</em> specifies how long the system waits for the specified signal flags. While the system waits the thread calling this function is put into the state <b>WAITING</b>. The timeout value can have the following values:</p>
<ul>
<li>when <em>millisec</em> is 0, the function returns instantly.</li>
<li>when <em>millisec</em> is set to <b>osWaitForever</b> the function will wait for an infinite time until a specified signal is set.</li>
<li>all other values specify a time in millisecond for a timeout.</li>
</ul>
<p><b><a class="el" href="group__CMSIS__RTOS__Status.html">Status and Error Codes</a></b><br/>
</p>
<ul>
<li><em>osOK:</em> no signal received when the timeout value <em>millisec</em> was 0.</li>
<li><em>osEventTimeout:</em> signal not occurred within timeout</li>
<li><em>osEventSignal:</em> signal occurred, <em>value.signals</em> contains the signal flags; these signal flags are cleared.</li>
<li><em>osErrorValue:</em> the value <em>signals</em> is outside of the permitted range.</li>
<li><em>osErrorISR:</em> <a class="el" href="group__CMSIS__RTOS__SignalMgmt.html#ga38860acda96df47da6923348d96fc4c9">osSignalWait</a> cannot be called from interrupt service routines.</li>
</ul>
<dl class="section note"><dt>Note</dt><dd>Cannot be called from <a class="el" href="functionOverview.html#CMSIS_RTOS_ISR_Calls">Interrupt Service Routines</a>.</dd></dl>
<p><b>Code Example</b> </p>
<div class="fragment"><div class="line"><span class="keywordtype">void</span> Thread_2 (<span class="keywordtype">void</span> <span class="keyword">const</span> *arg);</div>
<div class="line">  </div>
<div class="line"><a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaee93d929beb350f16e5cc7fa602e229f">osThreadDef</a> (Thread_2, <a class="code" href="cmsis__os_8h.html#ga7f2b42f1983b9107775ec2a1c69a849aa914433934143a9ba767e59577c56e6c2">osPriorityHigh</a>, 1, 0);</div>
<div class="line">   </div>
<div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span> EX_Signal_1 (<span class="keywordtype">void</span>)  {</div>
<div class="line">  <a class="code" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a> thread_id;</div>
<div class="line">  <a class="code" href="group__CMSIS__RTOS__Definitions.html#structosEvent">osEvent</a> evt;</div>
<div class="line">    </div>
<div class="line">  thread_id = <a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gac59b5713cb083702dce759c73fd90dff">osThreadCreate</a> (<a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaf0c7c6b5e09f8be198312144b5c9e453">osThread</a>(Thread_2), NULL);</div>
<div class="line">  <span class="keywordflow">if</span> (thread_id == NULL)  {</div>
<div class="line">    <span class="comment">// Failed to create a thread.</span></div>
<div class="line">  }</div>
<div class="line">  <span class="keywordflow">else</span>  {</div>
<div class="line">    :</div>
<div class="line">    <span class="comment">// wait for a signal</span></div>
<div class="line">    evt = <a class="code" href="group__CMSIS__RTOS__SignalMgmt.html#ga38860acda96df47da6923348d96fc4c9">osSignalWait</a> (0x01, 100);</div>
<div class="line">    <span class="keywordflow">if</span> (evt.<a class="code" href="group__CMSIS__RTOS__Definitions.html#ad477a289f1f03ac45407b64268d707d3">status</a> == <a class="code" href="group__CMSIS__RTOS__Status.html#gae2e091fefc4c767117727bd5aba4d99ea5df7e9643aa8a2f5f3a6f6ec59758518">osEventSignal</a>)  {</div>
<div class="line">          <span class="comment">// handle event status</span></div>
<div class="line">    }</div>
<div class="line">  }</div>
<div class="line">}</div>
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